The present invention relates to a method for controlling a paging system, and more particularly to a method for controlling transmission in a wide area radio paging system to thereby maintain a reference channel of the wide area radio paging system.
A conventional radio pager (i.e., paging receiver) has a disadvantage in that paging service can only be provided to a single localized area, but cannot be provided nationwide. To solve this problem, a wide area paging system (PS) has been developed which can provide a wide area paging service. In other words, the conventional local area paging service has been expanded to provide service throughout the country. Accordingly, a wide area paging system configuration has been developed to accommodate the wide area paging service.
Wide area paging systems can be classified into two general types. With the first type of system, radio frequency channels (RFCH) are utilized for local paging areas, and an exclusive radio frequency channel (RFCH) is separately utilized for providing the wide area paging service. Channel transmitters are provided for transmitting paging frequencies of the radio frequency channels (RFCH). This first type of system, however, has a problem in that the exclusive radio frequency channel (RFCH) is responsible for providing paging service to all areas. Accordingly, the number of subscribers to which the wide area paging service can be provided is limited since only one exclusive radio frequency channel (RFCH) is utilized, thereby resulting in a limited frequency band.
With the second type of paging system, an exclusive radio frequency channel (RFCH) is not utilized for providing the wide area paging service. Instead, several radio frequency channels (RFCHs) utilized for various local areas are used to form a paging network over the entire country. In other words, the radio pager in this type of system is provided with radio frequency channels (RFCHs) for paging service in a local area, and is additionally provided with radio frequency channels (RFCH) for paging service in other areas outside the local area. The radio pager is provided with a plurality of reference channels (about 10 reference channels) which each represent a different local area, and is also provided with a plurality of service channels (about 10 service channels).
The reference channel is a channel for a frequency that allows the radio pager to discern a desired paging service area. That is, the reference channel refers to a radio frequency channel (RFCH) for searching for a desired paging service area. The service channel is a channel utilized as a message receiving channel by an incoming call after the desired paging service area is searched for according to the reference channel, in cases where subscribers carrying the radio pagers move around the paging service areas.
The second type of paging system described above, however, has a problem in that when a radio pager determines the desired paging service area by receiving a reference frequency of the reference channel, if an incoming paging signal of the reference channel is not generated in the desired paging service area, paging service cannot be provided to the radio pager.
For example, when the incoming paging signal is not generated through the reference channel of a given paging service area in the paging system within a given time period (e.g., incoming paging signals are not frequently generated between 4 o'clock and 7 o'clock in the morning), the paging signal cannot be transmitted to the desired radio pager through the radio frequency channel (RFCH) of the reference channel. Accordingly, there is a problem in that if the paging signal is not transmitted through the reference channel of the desired paging service area, the radio pager determining the desired paging service area by receiving the reference frequency through its reference channel automatically changes the reference channel of the desired paging service area to other reference channels of other paging service areas as a receiving channel to thereby receive other reference frequencies through the reference channels of other paging service areas. As a result, the radio pager cannot be provided with paging service in a given area in which it is actually situated. For example, if the incoming paging signal is not received within a given period of time (typically, about 10 seconds), the radio pager automatically changes the reference channel corresponding to an `A` area to a reference channel corresponding to a "B" area, thereby making it impossible for the radio pager to be provided with paging service in the "A" area even when the radio pager is actually situated in the "A" area.